The present invention relates generally to liquid crystal displays, and more specifically to an active matrix liquid crystal display.
To overcome shortcomings inherent to nonactive liquid crystal displays, active matrix liquid crystal displays have been developed so far using switching elements at intersections of X-Y electrodes. For large panel applications, the most promising device for the switching element is a metal-insulator-metal structure in which the insulator is composed of silicon nitride as described in M. Suzuki et al. "A New Active Diode Matrix LCD Using Off-Stoichiometric SiNx Layer", Proceedings of the SID, Vol. 28 pages 101-104, 1987. While satisfactory in terms of its high nonlinear coefficient and low manufacturing cost, one shortcoming of the MIM structure is that a short circuit can occur in the insulator due to its small thickness (which is typically 100 nanometers), causing pin-hole defects which result in a low yield during manufacture. A further disadvantage of the prior art display is that it flickers when voltages of opposite polarity are applied since the voltage-current characteristic is asymmetric with respect to different polarities.